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June 5, 1928. 1,672,318

R. M. HINRICH LOCK TYPE DAMPER REGULATOR Filed April 11, 1927 ,25 /07 l W ,x ff n, 2 ivd/T20 u M Q 176 WH Mm] 8 Hl u i' 2f i 7 /0 2 xfa L* 7 /4 d 7 i Patented June. 5, 1928.

UNITED STATES PATENT ermee.

noBERT rr, "HINRICH, ory DETROIT, MIVCVHIGAM AsstGNoR To nnnxn'nvna colu- PANY, or niiTRornMrcHreAN, A CORPORATION or MrcmGaN.

LoCK-TYrE-DAMPER REGULATOR.

` Application led April 11,

This invention relates generally to damp ers for controlling thevolume ofair pass` ingthrough heating and Ventilating ducts and "refers lmore particularly to locking means for dampers of theftype specified.

In heating systems wherefthe ordinary type of dampers are in use, it is of course readily apparent that any unauthorized'person may tamper with and operate said damper. It has been found that where dampers are pro# vided in heating Y systems used in schools, that the children will unintentionally tamper with the same and cause much inconvenience and unnecessarytrouble. It is therefore one of the essential objects of ythe present invention to eliminate such objectionable features and provide dempers which are capable of being locked in their various positions of adjustifient and which can be operated only by those persons having keys to itsuch locking mechanism.

It is another object of this invention to enclose the locking mechanism in a tamper proofcasing, but to provide means for indieating. at Iall times the different positions 'to which the damper has been moved.'y l,

Withthese and other objects in viewi'the invention resides in the novelkfeaturesl` of construction and combination and arrangement of partsas more fully yhereinafter set forth. f

In the accompanying drawings:

Figure 1 is a section through a heating or ventilator duct showing the damper together with the locking means therefor;

Figure 2 is a front elevation of the locking means with a portion of the casing broken away.

Figure 3 is a section taken on line 3-3 of Figure 2;

Figure 4 is a detail of the key for actuating the locking mechanism. y

Figure 5 is an end elevation ot the key.

In they drawings wherein like characters of referenceindicate like parts the numeral 1 designates an ordinary heating or ventilating duct having mounted therein a damper 2 which is carried by the transversely extending shaft 3. As shown, this shaft is journalled in opposite walls of the duct, having one end portion 4 provided with a transverse j opening to accommodate a Cotterl pin 5 and having its other` end terminating in a squared portion 6.

1927. -ser'ial No. matias.V j*

Secured tothe outside of oneof the walls of the duet 1 is a casing 7 having inner and outerY walls 8 and 9 connected by -ineans'y of*v en annular wall 10. Suitably mounted Within this casing is a toothed wheel ll'pr'ovided witha square opening 12 for reeeiv'ing`the square end portion 6 of the shaft 3.

As shown,v theinne'r wall 8 of the casing is provided with a circular opening 13.y and the gear wheelfll is' provided with 'an annular shoulder1-4 fitting within thisopening and tending to position'theA wheel eentrallv within the casing-- n Win ofcourse be noted that the' toothedy wheelY is provided with a raised portion 15 extending laterally outward from the teeth 1.6 and having a Hat face portion .15 arranged to fit against the inside surf-ace of the outer casing wall 9.

As shown in Figure eithere is provided a key 17fhaving the handle portion 18 and the shank 19 whic'his provided at one end with teeth 20 of substantial-ly thevsam'e pitch asthe teeth of the wheel 11. The end portion of the shank 19 earryng'the-teeth. 20 is also providedwith a longitudinally extending recess 21 and the inner wal-l 8 of the casing is provided with a stud 22'pro'ec`ting therefrom and arranged to engage. the slot- 21 so as to pivotally position the Vkey with respect yto the toothed wheel. n As will :be noted the, easing. is provided with an opening 23 so designed as to allow for the insertion of the key in the casing with the teeth 20 turned away from the toothed wheel. However, just as soon as the key 17 is inserted in the casing it ma be rotated upon thestud 22 so that the teet 20 mesh with the 'teeth 16 and thereby i rotate the gear wheel and damper a certain.

predetermined distance. j

For retaining the toothed wheel and damper in different positions of adjustmentthere vis provided a spring 24`having the armporthe damper and in addition there are sixy intermediate points indicating steps between the complete lopen andy closed positions. An opening 28 is provided in the outer Wall of the casing registering With the peripheral` portions of the face for presenting the different letters and numerals when vthe damper is moved to different positions. It Will thus be seen that no one will be able to operate the damper Without lirst inserting a -key through the opening 23 and then 1 turning the same so thatthe teeth of the key mesh With the teeth 16 of the toothed Wheel. The key may be rotated until the desired position of the damper. is obtained Whereupon it-may be easily removed by allowing the teeth 2O to register vWith the opening 23.

Vhile it is believed that from the foregoing description, the nature and advantage of my invention Will be readily understood, I desire to have it understood that I do not limit myself to the specific construction shown and described and that such changes may be resorted to When desired as fall Withinthe scope of the claims.

,What I claim as my invention is 1. In combination, a flue, a damper pivotally mounted Within said flue, and means for locking said damper in diii'erent positions of adjustment including a` Wheel rotatable With said damper, and adapted to vhave its periphery engaged by a key for end of said shaft outside of said flue', and adapted to be actuated by a key.v

l. In combination, a flue, a damper, a shaft for supporting said damper journalled in said Hue, a casing secured exterior-ly of said iiue, and a toothed Wheel Within said casing and securedto saidy shaft, and said casing being provided with an opening' 6. In combination, a. flue, a damper'pivotally mounted Within said flue, means for locking said damper in different positions of adjustment including a member movable` With lsaid damper, and adapted to vbe actuated by a keyandindicia uponfsaid member for indicating the various positions of adjustment of the damper.

7. In combination, a iue, a damper, a shaft for supporting said damper j ournalled in said flue, a casing secured eXteriorly of said ue and having an opening in its outer Wall, a key operated toothed Wheel Within said casing and secured to said shaft, and indicia upon said Wheel adapted to register With said casing lopening for indicating the various positions of adjustment of said damper.

In testimony whereof I aiiixrmy signature...4

ROBERT M. iiiuni'on.' l 

